1. Field of the Invention
The present invention relates to a multi-plate friction clutch.
2. Description of Background Art
A wet multi-plate friction clutch is generally known, wherein a plurality of clutch plates and a plurality of friction plates are alternately disposed in an overlapping manner in a ring-shaped space between an outer cylindrical part of a clutch outer. A center cylindrical part of a clutch center is set between a center bottom wall part of the clutch center and a pressure plate.
To enhance the durability and smoothly perform connection and disconnection, oil needs to be sufficiently supplied to the plurality of clutch plates and the plurality of friction plates alternately overlapped.
In one related-art example, because oil leaking from a bearing for rotatably journaling an outer bottom wall part of the clutch outer around a rotation shaft flows out to a space between the outer bottom wall part and the center bottom wall part, a communication hole (oil conduction hole) that allows the outer surface side and the inner surface side to communicate with each other is formed in the center bottom wall part to thereby supply oil that flows out to the space between the outer bottom wall part and the center bottom wall part to the friction plates and the clutch plates on the inner surface side of the center bottom wall part via the communication hole. See, for example, Japanese Patent Laid-Open No. Sho 60-234126.
In the multi-plate friction clutch disclosed in Japanese Patent Laid-Open No. Sho 60-234126, the oil guided from an oil passage formed in the rotation shaft to the bearing leaks from the bearing and flows out to the space between the outer bottom wall part and the center bottom wall part. Then, part of the oil that has flowed out flows in a centrifugal direction along the outer surface of the center bottom wall part and furthermore part of this oil passes through the oil conduction hole to enter the inner surface side of the center bottom wall part.
The oil that has passed through the oil conduction hole is guided to the inner circumferential surface of the center cylindrical part on the inner surface side of the center bottom wall part and exits from a plurality of small holes formed in the center cylindrical part to the outer circumferential side of the center cylindrical part to be supplied to the clutch plates and the friction plates alternately overlapped.